The present invention relates to a method and an arrangement for influencing the interaction between a layer of earth and a structure situated in association with the layer of earth. The expression structure is used primarily to denote buildings, tunnels, foundations, devices which produce vibrations and similar. The arrangement, which is in the form of a casing filled with a medium, is intended first and foremost to be arranged close to or in direct association with said structure in a material surrounding the casing.
The arrangement of gas-filled mattresses in earth or water for vibration-damping purposes is previously disclosed. A previously disclosed mattress is the so-called single-cell mattress described in SE-B-8202478-7 (publication No. 430 620). Since this mattress is arranged essentially vertically, and is then filled with a gas, its final geometry in the installed position is not apparent. Mattresses of this kind are frequently forced down to considerable depths, where the surrounding pressure is very high. This makes the mattress difficult to fill with gas, and there is also a risk that it will adopt a pear-shaped cross-section with the narrowest part at the bottom. This form has a negative influence on the vibration-damping characteristics of the mattress. In order to improve the mattress, U.S. Pat. No. 4,647,258 proposes a mattress made of a flexible, multi-layer membrane. In this mattress it is possible to adapt the pressure to the surrounding pressure of the earth at different depths, at the same time as the smaller cells make the mattress less sensitive to puncturing. The mattress is intended to be arranged essentially vertically, with the elongated cells running horizontally. Any vibrations present in the earth which strike the mattress essentially at right-angles or to all intents and purposes at right-angles will be damped effectively. However, the mattress is less well suited to the damping of vibrations in its longitudinal direction. The force-absorbing capacity of the mattress in said direction is likewise restricted.